As poverty increased, more and more New Zealanders were not paid enough to meet their needs, enjoy their lives and participate in society, he said.
"We wanted to do something about that.
"We've worked out that we can afford to pay our staff at least $18.40 if we tighten up in other budget areas.
"That was the big decision for the board of trustees."
"We've had to make decisions like having a classroom full of iPads or a high quality teacher aide.
"A teacher aide has far more education value in my eyes."
Joining the movement meant pay rises for half a dozen staff, and now all staff were paid a minimum of $18.40 an hour, he said.
He declined to say how much extra it was costing the school to meet the living wage cost, saying it was personal information.
The NZEI teachers union and the Living Wage Movement both said the school was the first to adopt the wage.
The living wage movement was launched in New Zealand in May last year, and is modelled on living wage campaigns around the world.
A public meeting at 5.30pm tomorrow at Dunedin North Intermediate is to launch a Dunedin group supporting the Living Wage Aotearoa campaign.
Service and Food Workers' Union communications director Lyndy McIntyre, who will speak at the meeting, said yesterday the campaign had already achieved success around the country, with the Wellington City Council and The Warehouse announcing steps to move towards adopting a living wage.
The Dunedin City Council has been asked to support the campaign, and council managers are now studying the impact adopting the minimum of $18.40 an hour wage would have on its salary structure.